Following the Alzheimer’s Association International Conference, we caught up with Sarah Gregory, PhD student and Study Coordinator for PREVENT in Edinburgh to discuss all the latest research developments from across the globe.
July saw the world’s largest dementia conference hosted in Los Angeles. Experts from around the world attend this conference and this year there were nearly 6000 attendees, with many early career researchers making up this number.
The 2019 conference agenda was noticeably even more diverse than usual, in light of recent failures of drugs targeting the amyloid protein. Many sessions focussed on the many new ways scientists are working to understand the diseases that cause dementia.
Lifestyle and the environment
As the coordinator of the PREVENT and EPAD studies, and a PhD student looking at midlife stress, the epidemiology sessions always catch my eye, and the majority of talks I attended outside of the plenary sessions were in these streams. Some key take away messages were:
Sleep was a hot topic of this conference with more than one parallel session featuring excellent presentations on work going on in this area. One of these talks was by Jennifer Zitser (Global Brain Health Institute) who presented work from the Whitehall II imaging study. In this study, she looked at the extremes of sleep, that is sleep of less than 6 or more than 9 hours a night, and how that relates to grey matter volume (the amount of brain cells packed into a particular brain region) and cognition. There were no significant findings by hours of sleep with any measures of cognition or imaging variables (grey matter volume, white matter integrity and atrophy). Additional analysis included self-reported quality of sleep and found that this, rather than the total of hours of sleep, may be where the benefit and harm lies. Further work is needed to understand how sleep relates to Alzheimer’s disease (AD).
Body mass index
Body mass index, or BMI, was another featured topic, and I attended two interesting presentations on this.
The first was presented by Kristine Yaffe (University of California, San Francisco) who used multiple cohorts (from young children through to older adults) to understand when and how cardiovascular risk factors interplay with age. In her presentation, she found that higher BMI and fasting glucose (blood sugar levels) in early adult and mid-life were related to more cognitive impairment in older life, whilst higher BMI in late life was related to less cognitive decline after 80.
The second was from Willa Brenowitz (also UCSF) who also presented her work on comparing Alzheimer’s disease genetic risk scores (a combination of 23 genes that add varying levels of risk to developing AD) and BMI in the UK Biobank cohort. Her work found that lower BMI at age 56 and above was associated with the lowest and highest AD genetic risk scores. More research is needed to understand the relationship between BMI and cognitive impairment, and particularly how the risk or benefit from BMI may vary across the lifespan.
Women who spent time in the paid labour force had a slower cognitive decline compared to those who did not. Elizabeth Rose Mayeda (UCLA) presented work looking at gender as a social construct as opposed to the female sex as a biological construct. The study took data from the Health and Retirement Study and grouped participants by patterns of work depending on if they had every worked, had been married and/or had children. Compared to those who had never worked, women who had engaged with the work force in early to mid-life experienced a slower decline in their memory and thinking, by an average of 5 years.
Attending a conference is a great way to hear about the novel approaches being taken by research teams around the world. An area that I think we’ll hear more about in the coming months and years is that of disclosing to individuals their genetic status for the APOE4 gene, a gene implicated in increased risk for Alzheimer’s disease. The SOKRATES2 study adds valuable information to this discussion:
Emily Largent presented on the SOKRATES2 study and spoke about APOE4 disclosure. The National Institute on Ageing (NIA) discourage APOE4 testing currently due to little clinical or diagnostic benefit. However in research settings this is changing. Individuals may want to know their genetic results if it has been tested as part of a research study, and some trials either enrol people based on genetic status or adjust treatment doses for this. As such we need to understand how people react to the disclosure of a risk gene. The SOKRATES 2 study was a qualitative study of participants who learned their genotype as part of the Novartis GENERATION programme. In SOKRATES 2 participants were asked about their experiences of learning their genetic result for the APOE4 gene. The outcomes generally support the growing consensus that disclosure was safe. Non-carriers were 90% positive about disclosure and none were negative. A third of the participants who carried 2 copies of the gene (those at the higher level of risk for developing AD) expressed a neutral view about finding out their results.
The study found that the SOKRATES 2 participants – who were cognitively healthy (had no detectable problems with their memory of thinking) though often had a family history of AD – generally had a good understanding of the risk of their gene status. Many APOE4 carriers adopted new health behaviour at 3 months (such as diet changes) and nearly half of carriers made or contemplated changes to future plans. Participants frequently spoke to their family, both as a confidant and in cases of children or siblings because they may want to know about their own genetic risk. Participants who chose not to share their genetic results did not want to distress others and expressed a fear of discrimination.
Cortisol and stress
My own PhD looks at stress in midlife as a risk factor for Alzheimer’s disease and I was really looking forward to attending a session about the STRIDE study:
STRIDE is the Stress, Resilience and Inflammation in Dementia study, which was presented by Megan Zuelsdorff (University of Wisconsin-Madison). Previous research has found that perceived stress and recent stressful events have been associated with socioeconomic disadvantage and racial/ethnic minority. What is still not understood is whether this is more relevant at certain times or for certain populations. This study aims to understand how stress and resilience interplay with risk for cognitive aging, particularly focusing on groups of participants from rural residences and non-Caucasian populations. Participants complete questionnaires and saliva samples which will be analysed for cortisol, the stress hormone in humans.
AAIC has such a huge agenda that it’s impossible to attend everything you want, and this blog gives just a glimpse into the many exciting session that were available during the conference.
If you’re interested in finding out more about the science discussed at AAIC I recommend you have a listen to the excellent Dementia Researcher podcasts which are recorded each day at the conference. These are 35-40 minute episodes discussing the highlights of each day for the panel.
Sarah Gregory is a doctoral candidate with the Edinburgh Dementia Prevention Research Group at the University of Edinburgh and a Study Coordinator for the PREVENT Dementia Research Programme and European Prevention of Alzheimer’s Dementia (EPAD) Consortium.